package com.google.gwt.sample.stockwatcher.client;

import java.util.ArrayList;
import java.util.Date;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyPressEvent;
import com.google.gwt.event.dom.client.KeyPressHandler;
import com.google.gwt.i18n.client.DateTimeFormat;
import com.google.gwt.i18n.client.NumberFormat;
import com.google.gwt.user.client.Random;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.FlexTable;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.VerticalPanel;

public class StockWatcher implements EntryPoint {
	private static final int REFRESH_INTERVAL = 5000; // ms
	private VerticalPanel mainPanel = new VerticalPanel();
	private FlexTable stocksFlexTable = new FlexTable();
	private HorizontalPanel addPanel = new HorizontalPanel();
	private TextBox newSymbolTextBox = new TextBox();
	private Button addStockButton = new Button("Add");
	private Label lastUpdatedLabel = new Label();
	private ArrayList<String> stocks = new ArrayList<String>();
	private StockPriceServiceAsync stockPriceSvc = GWT.create(StockPriceService.class);
	private Label errorMsgLabel = new Label();
	
	/**
	 * Entry point method
	 */
	public void onModuleLoad() {
		// Create table for stock panel.
		stocksFlexTable.setText(0, 0, "Symbol");
		stocksFlexTable.setText(0, 1, "Price");
		stocksFlexTable.setText(0, 2, "Change");
		stocksFlexTable.setText(0, 3, "Remove");
		
		// Add styles to elements in the stock list table.
		stocksFlexTable.setCellPadding(6);
		stocksFlexTable.getRowFormatter().addStyleName(0, "watchListHeader");
		stocksFlexTable.addStyleName("watchList");
		stocksFlexTable.getCellFormatter().addStyleName(0, 1, "watchListNumericColumn");
		stocksFlexTable.getCellFormatter().addStyleName(0, 2, "watchListNumericColumn");
		stocksFlexTable.getCellFormatter().addStyleName(0, 3, "watchListRemoveColumn");
		
		// Assemble Add Stock panel.
		addPanel.add(newSymbolTextBox);
		addPanel.add(addStockButton);
		addPanel.addStyleName("addPanel");
		
		// Assemble Main panel.
		errorMsgLabel.setStyleName("errorMessage");
		errorMsgLabel.setVisible(false);
		
		mainPanel.add(errorMsgLabel);
		mainPanel.add(stocksFlexTable);
		mainPanel.add(addPanel);
		mainPanel.add(lastUpdatedLabel);
		
		// Associate the Main panel with the HTML host page.
		RootPanel.get("stockList").add(mainPanel);
		
		// Move cursor focus to the input box
		newSymbolTextBox.setFocus(true);
		
		// Setup timer to refresh list automatically.
		Timer refreshTimer = new Timer() {
			@Override
			public void run() {
				refreshWatchList();
			}
		};
		refreshTimer.scheduleRepeating(REFRESH_INTERVAL);
		
		// Listen for mouse events on the Add button.
		addStockButton.addClickHandler(new ClickHandler() {
			public void onClick(ClickEvent event) {
				addStock();
			}
		});
		
		// Listen for keyboard events in the input box.
		newSymbolTextBox.addKeyPressHandler(new KeyPressHandler() {
			public void onKeyPress(KeyPressEvent event) {
				if (event.getCharCode() == KeyCodes.KEY_ENTER) {
					addStock();
				}
			}
		});
	}
	
	/** Add stock to FlexTable. Executed when the user clicks the addStockButton
	 * or presses Enter in the newSymbolTextBox
	 */
	private void addStock() {
		final String symbol = newSymbolTextBox.getText().toUpperCase().trim();
		newSymbolTextBox.setFocus(true);
		
		// Stock code must be between 1 and 10 characters that are numbers, letters, or dots.
		if (!symbol.matches("^[0-9A-Z\\.]{1,10}$")) {
			Window.alert("'" + symbol + "' is not a valid symbol.");
			newSymbolTextBox.selectAll();
			return;
		}
		
		newSymbolTextBox.setText("");
		
		// Don't add the stock if it's already in the table.
		if(stocks.contains(symbol))
			return;
		
		// Add the stock to the table.
		int row = stocksFlexTable.getRowCount();
		stocks.add(symbol);
		stocksFlexTable.setText(row, 0, symbol);
		stocksFlexTable.setWidget(row, 2, new Label());
		stocksFlexTable.getCellFormatter().addStyleName(row, 1, "watchListNumericColumn");
		stocksFlexTable.getCellFormatter().addStyleName(row, 2, "watchListNumericColumn");
		stocksFlexTable.getCellFormatter().addStyleName(row, 3, "watchListRemoveColumn");
		
		// Add a button to remove this stock from the table.
		Button removeStockButton = new Button("x");
		removeStockButton.addStyleDependentName("remove");
		removeStockButton.addClickHandler(new ClickHandler() {
			public void onClick(ClickEvent event) {
				int removedIndex = stocks.indexOf(symbol);
				stocks.remove(removedIndex);
				stocksFlexTable.removeRow(removedIndex + 1);
			}
		});
		stocksFlexTable.setWidget(row, 3, removeStockButton);
		
		// Get the stock price.
		refreshWatchList();
	}
	
	/**
	 * Generate random stock prices
	 */
	private void refreshWatchList() {
		// Initialize the service proxy.
		if(stockPriceSvc == null) {
			stockPriceSvc = GWT.create(StockPriceService.class);
		}
		
		// Set up the callback object.
		AsyncCallback<StockPrice[]> callback = new AsyncCallback<StockPrice[]>() {
			public void onFailure(Throwable caught) {
				// If the stock code is in the list of delisted codes, display an error message.
				String details = caught.getMessage();
				if(caught instanceof DelistedException) {
					details = "Company '" + ((DelistedException)caught).getSymbol() + "' was delisted";
				}
				
				errorMsgLabel.setText("Error: " + details);
				errorMsgLabel.setVisible(true);
			}
			
			public void onSuccess(StockPrice[] result) {
				updateTable(result);
			}
		};
		
		// Make the call to the stock price service.
		stockPriceSvc.getPrices(stocks.toArray(new String[0]), callback);
	}
	
	/**
	 * Update the Price and Change fields for all the rows in the stock table.
	 * 
	 * @param prices Stock data for all rows.
	 */
	private void updateTable(StockPrice[] prices) {
		for (int i = 0; i < prices.length; i++) {
			updateTable(prices[i]);
		}
		
		// Display timestamp showing last refresh.
		lastUpdatedLabel.setText("Last update : " + DateTimeFormat.getMediumDateTimeFormat().format(new Date()));
		
		// Clear any errors.
		errorMsgLabel.setVisible(false);
	}
	
	private void updateTable(StockPrice price) {
		// Make sure stock is still in the stock table
		if (!stocks.contains(price.getSymbol())) {
			return;
		}
		
		int row = stocks.indexOf(price.getSymbol()) + 1;
		
		// Format the data in the Price and Change fields.
		String priceText = NumberFormat.getFormat("#,##0.00").format(price.getPrice());
		NumberFormat changeFormat = NumberFormat.getFormat("+#,##0.00;-#,##0.00");
		String changeText = changeFormat.format(price.getChange());
		String changePercentText = changeFormat.format(price.getChangePercent());
		
		// Populate the Price and Change fields with new data.
		stocksFlexTable.setText(row, 1, priceText);
		Label changeWidget = (Label)stocksFlexTable.getWidget(row, 2);
		changeWidget.setText(changeText + " (" + changePercentText + "%)");
		
		// Change the color of text in the Change field based on its value
		String changeStyleName = "noChange";
		if (price.getChangePercent() < -0.1f) {
			changeStyleName = "negativeChange";
		}
		else if (price.getChangePercent() > 0.1f) {
			changeStyleName = "positiveChange";
		}
		
		changeWidget.setStyleName(changeStyleName);
	}
}